I think they're saying you create your own malicious wifi network and people will unintentionally connect to it. This network specifies your malicious DNS server via DHCP, and everything looks secure to the client. I think the main issue with this in practice is that all the major browsers have been updated to not trust these certs.

They wouldn't. A device like the Pineapple broadcasts its own copycat wireless signal and tricks unsuspecting clients to connect to it thinking it's the real one.

Edit: Holy moly we all jumped on this comment at the same time didn't we.

They don't need to, a Pineapple (or anything else that can run a wireless access point, you could do this with a laptop) just needs to advertise the expected SSID and do so with a stronger signal than the official ones for people's devices to connect to it instead of the actual network.

It’s extremely common to see other Macs pop up in the ‘network’ panel in Finder in the independent coffee shops around me. I imagine they’re just signing up for a business plan and using the routers the ISP gives them with a custom SSID and password.

You dont interact with anyone. You just set your own hotspot and people will connect to it.